Outraged visitors to Paris -- as well as Parisians themselves -- have posted warnings against the pickpocketing epidemic on Twitter.

"The annual August exodus from Paris has begun, the 7th arrondissement is deserted, only beggars, pickpockets ... and tourists [remain]," reads one post.

Another tweet warns, in French, of the latest pickpocketing technique: a thief pretends to be disabled and asks for your seat on the metro, only to relieve you of your possessions as you clumsily swap places.

Tourists from China not only often trust cash over cards but also, along with Russians, are among the biggest spenders in Paris -- and they often spend indiscreetly.

"I, and many people I know, have often been approached by the Asian tourists thronging outside the Louis Vuitton store on the Champs-Elysées, who approach you with cash to buy bags for them, as the store limits each customer to two," Paul Roll, director of the Office du Tourisme de Paris, told the Telegraph.

French officials have acknowledged the pickpocketing surge, putting 200 extra police on patrol around top tourist attractions and publishing a "Guide to Staying Safe in Paris" in Chinese, Japanese, Korean and Spanish -- one of several such guides acknowledging the extent of the problem.

The Paris police advice goes little beyond the need to be vigilant, but it does warn against carrying a backpack -- which can easily be pilfered because it's usually out of direct view.

It also says some thieves in Paris are impersonating police and asking for ID and proof that tourists are carrying money, which they then try to snatch.

Perhaps the most widely noted pickpocketing technique is for thieves to approach marks at cash registers, asking if they can help with a "petition."

As they loiter, they note the customers' PINs, then follow them and pickpocket their cards to withdraw money themselves later.

"Make a copy of your passport, and front and back of everything that you have in your wallet," is some of its less obvious advice.

"Ladies," it says, "only carry purses that zip."

The guide also warns against another pickpocketing technique -- the metro "crush and grab," whereby a bunch of fellow "passengers" jostle you and pick your pocket as you get on or off a train.

Spilling water or ice cream on a potential victim is yet another method. Profusely apologizing, one of a pickpocketing pair will vigorously dust you down after the fake accident, while a collaborator steals your wallet or camera.

Don't wear shorts

So recognized is the Paris pickpocketing problem, that even TripAdvisor has a dedicated page of advice. It recommends the BeSafe smartphone app, created by a pair of French students, which collates data from police reports to display the most crime-prone areas in Paris in real time.

It also suggests how not to look like an obvious tourist.

Use the small "Paris Pratique" guide, it says, favored by French visitors to the city, rather than a large foldout map.